| 摘要 |
PURPOSE:To enable the excitation of the surface wave pulse having sufficient strength for the inspection of the surface flaw of the object surface having a finite curvature by arranging in opposition on the surface of a body the plural ultrasonic oscillators positioned by adjoining each other and by setting according to the curvature of the body surface the impressing timing of the electric pulse for ultrasonic excitation to be impressed on individual oscillator thereof. CONSTITUTION:The curvature of the surface of a large diameter steel pipe 10 is inputted on an arithmetic processing part 33 from a setter 34. A synchronous signal generator 31 transmits a clock pulse and delay circuit 32(1)-32(N) delays the clock pulse by the part of the time inputted from the arithmetic process part 33 and feeds it as a trigger pulse to electric pulse transmitter 21(1)-21(N). The transmitters 21(1)-21(N) impress the electric pulse on each ultrasonic oscillator 11(1)-11(N) being incorporated in the tyre type probe 8 being pushed to the surface of the steel pipe 10. The surface wave pulse excited by the ultrasonic pulse to be transmitted from the oscillator 11(1)-11(N) is overlapped and strengthened each other, making sufficient strength for the inspection of the surface flaw. |
